In some applications, it is necessary to couple a first shaft and a second shaft together, where the first shaft is a driving shaft, such that the first shaft comes to drive the second shaft.
An example of such an application is a wind power plant, where a gearbox shaft has to be coupled to a generator shaft. Such elastic couplings must be able to take up some deviations in the alignment of the shafts and are previously known. Such an elastic coupling, or coupling member, normally consists of a rigid shaft part and of two resilient bushings at each end of the rigid shaft part. The resilient bushings are normally mounted on the respective first and second shaft via suitable flanges.
It is of course preferable for the alignment between the first shaft and the second shaft to be as correct as possible, for which reason a manual alignment is nowadays carried out during assembly using the necessary measuring equipment, for example laser-based measuring equipment.
However, there is a need to be able to measure the alignment between the first shaft and the second shaft, that is to say the alignment of the coupling member, continuously during operation, which cannot be done using existing measuring equipment. Since the shafts concerned are rotating shafts, measuring equipment must not create an imbalance when mounted. It is also desirable to be able to measure this alignment using existing structures, without causing damage to them.
It is also desirable to be able to detect other operating data, such as the torque transmitted by the coupling being able to be detected by measuring the position of the coupling member.
It is therefore necessary to be able to measure the position of a coupling member between a first shaft and a second shaft continuously during operation, where a rotation movement of the first shaft is transferred to the second shaft via the coupling member which elastically couples the first shaft to the second shaft, and where introduction of imbalance is also avoided.
It is also desirable that equipment for measuring the position of a coupling member can be mounted on existing equipment without the need for any mechanical working.